If I read you correctly, do you mean that he can't adopt the 'correct' positions to learn the movements for swimming, when the teacher asks?

If that's so, then he may need even more than one-to-one. Does the teacher get into the pool with him? Or is she giving verbal directions from the side? If he has sensory problems, it may be quite difficult for him to 'translate' verbal instruction to a movement pattern. He might be better being taught by having someone who will 'place' his limbs for him so that he can learn by the feeling. (hope that makes sense).

Also, in general, how is he with lying on his tummy and lifting his head up? (which is a movement replicated in front crawl).

He can adopt the correct positions, It's just his proprioception needs, easily put him back to a different one for learning the movements for swimming, after the teacher has asked.

I think the recommendation of swimming vest or belt should be tried so that his body has a reminder of where he is which I think proprioception essentially is.

He can learn the strokes and he can move himself through the water it just seems his altered sense of balance is putting him off. The OT has said that these children can learn to become desensitised which I am hoping with the help of a vest or weights.I agree he might be better being taught by having someone who will 'place' his limbs for him so that he can learn by the feeling too. It sounds as if it will take time refocusing him.

Teacher gets into pool with him as well as I do too to give him confidence to distract him from his echoey hearing senses too. I can see that it may be quite difficult for him to 'translate' verbal instruction to a movement pattern. Part of the reason I get in too is to translate what the teacher is saying to a more digestible form for him as she doesn't know him that well yet.

I'm sorry I don't know anything about your ds special needs but I am a swimming teacher. Try and get hold of a swimfin float. It looks like a sharks fin and straps to his back with elastic and Velcro straps. It's a bit like a bubble pack or a turtle shell but he will be able to use it for swimming on his back too and it's more stable than the other floats.

Teachers can be reluctant to manipulate limbs into swimming strokes but I think I would insist for your ds. This can be done out of the water too, which can be less distracting. I would ask for him to sit on the side to practice kicking with a teacher in the water keeping his legs straight, toes pointed etc. you can do the same with breaststroke arms, even at home, sitting on the sofa.

Apologies if I'm not offering advice that is suitable for your ds situation as I don't really know enough about it but hope something I have suggested might help. As always in swimming, keep smiling, lots of eye contact, lots of congratulating, clapping, whooping, encouragement, make it fun

Sorry, mean t to say that a back float strapped to his trunk will keep the heaviest part of his body afloat in a horizontal position so that he can concentrate on propulsion, breathing etc. not a fan of armbands as they restrict so much motion and floating on a noodle keeps children vertical, not horizontal.

It's actually called a swimfin http://www.swimfin.co.uk. Just bought one for my swimming lessons so that non independent learners can concentrate on propulsion without worrying about body position and buoyancy, they are a great idea and kids love them because of their shape.